<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Apc.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @see Zend_Cache_Backend_Interface
 */
require_once 'Zend/Cache/Backend/ExtendedInterface.php';

/**
 * @see Zend_Cache_Backend
 */
require_once 'Zend/Cache/Backend.php';

/**
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Cache_Backend_Apc extends Zend_Cache_Backend implements Zend_Cache_Backend_ExtendedInterface {
	/**
	 * Log message
	 */
	const TAGS_UNSUPPORTED_BY_CLEAN_OF_APC_BACKEND = 'Zend_Cache_Backend_Apc::clean() : tags are unsupported by the Apc backend';
	const TAGS_UNSUPPORTED_BY_SAVE_OF_APC_BACKEND = 'Zend_Cache_Backend_Apc::save() : tags are unsupported by the Apc backend';
	
	/**
	 * Constructor
	 *
	 * @param  array $options associative array of options
	 * @throws Zend_Cache_Exception
	 * @return void
	 */
	public function __construct(array $options = array()) {
		if (! extension_loaded ( 'apc' )) {
			Zend_Cache::throwException ( 'The apc extension must be loaded for using this backend !' );
		}
		parent::__construct ( $options );
	}
	
	/**
	 * Test if a cache is available for the given id and (if yes) return it (false else)
	 *
	 * WARNING $doNotTestCacheValidity=true is unsupported by the Apc backend
	 *
	 * @param  string  $id                     cache id
	 * @param  boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
	 * @return string cached datas (or false)
	 */
	public function load($id, $doNotTestCacheValidity = false) {
		$tmp = apc_fetch ( $id );
		if (is_array ( $tmp )) {
			return $tmp [0];
		}
		return false;
	}
	
	/**
	 * Test if a cache is available or not (for the given id)
	 *
	 * @param  string $id cache id
	 * @return mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
	 */
	public function test($id) {
		$tmp = apc_fetch ( $id );
		if (is_array ( $tmp )) {
			return $tmp [1];
		}
		return false;
	}
	
	/**
	 * Save some string datas into a cache record
	 *
	 * Note : $data is always "string" (serialization is done by the
	 * core not by the backend)
	 *
	 * @param string $data datas to cache
	 * @param string $id cache id
	 * @param array $tags array of strings, the cache record will be tagged by each string entry
	 * @param int $specificLifetime if != false, set a specific lifetime for this cache record (null => infinite lifetime)
	 * @return boolean true if no problem
	 */
	public function save($data, $id, $tags = array(), $specificLifetime = false) {
		$lifetime = $this->getLifetime ( $specificLifetime );
		$result = apc_store ( $id, array ($data, time (), $lifetime ), $lifetime );
		if (count ( $tags ) > 0) {
			$this->_log ( self::TAGS_UNSUPPORTED_BY_SAVE_OF_APC_BACKEND );
		}
		return $result;
	}
	
	/**
	 * Remove a cache record
	 *
	 * @param  string $id cache id
	 * @return boolean true if no problem
	 */
	public function remove($id) {
		return apc_delete ( $id );
	}
	
	/**
	 * Clean some cache records
	 *
	 * Available modes are :
	 * 'all' (default)  => remove all cache entries ($tags is not used)
	 * 'old'            => unsupported
	 * 'matchingTag'    => unsupported
	 * 'notMatchingTag' => unsupported
	 * 'matchingAnyTag' => unsupported
	 *
	 * @param  string $mode clean mode
	 * @param  array  $tags array of tags
	 * @throws Zend_Cache_Exception
	 * @return boolean true if no problem
	 */
	public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array()) {
		switch ($mode) {
			case Zend_Cache::CLEANING_MODE_ALL :
				return apc_clear_cache ( 'user' );
				break;
			case Zend_Cache::CLEANING_MODE_OLD :
				$this->_log ( "Zend_Cache_Backend_Apc::clean() : CLEANING_MODE_OLD is unsupported by the Apc backend" );
				break;
			case Zend_Cache::CLEANING_MODE_MATCHING_TAG :
			case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG :
			case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG :
				$this->_log ( self::TAGS_UNSUPPORTED_BY_CLEAN_OF_APC_BACKEND );
				break;
			default :
				Zend_Cache::throwException ( 'Invalid mode for clean() method' );
				break;
		}
	}
	
	/**
	 * Return true if the automatic cleaning is available for the backend
	 *
	 * DEPRECATED : use getCapabilities() instead
	 *
	 * @deprecated
	 * @return boolean
	 */
	public function isAutomaticCleaningAvailable() {
		return false;
	}
	
	/**
	 * Return the filling percentage of the backend storage
	 *
	 * @throws Zend_Cache_Exception
	 * @return int integer between 0 and 100
	 */
	public function getFillingPercentage() {
		$mem = apc_sma_info ( true );
		$memSize = $mem ['num_seg'] * $mem ['seg_size'];
		$memAvailable = $mem ['avail_mem'];
		$memUsed = $memSize - $memAvailable;
		if ($memSize == 0) {
			Zend_Cache::throwException ( 'can\'t get apc memory size' );
		}
		if ($memUsed > $memSize) {
			return 100;
		}
		return (( int ) (100. * ($memUsed / $memSize)));
	}
	
	/**
	 * Return an array of stored tags
	 *
	 * @return array array of stored tags (string)
	 */
	public function getTags() {
		$this->_log ( self::TAGS_UNSUPPORTED_BY_SAVE_OF_APC_BACKEND );
		return array ();
	}
	
	/**
	 * Return an array of stored cache ids which match given tags
	 *
	 * In case of multiple tags, a logical AND is made between tags
	 *
	 * @param array $tags array of tags
	 * @return array array of matching cache ids (string)
	 */
	public function getIdsMatchingTags($tags = array()) {
		$this->_log ( self::TAGS_UNSUPPORTED_BY_SAVE_OF_APC_BACKEND );
		return array ();
	}
	
	/**
	 * Return an array of stored cache ids which don't match given tags
	 *
	 * In case of multiple tags, a logical OR is made between tags
	 *
	 * @param array $tags array of tags
	 * @return array array of not matching cache ids (string)
	 */
	public function getIdsNotMatchingTags($tags = array()) {
		$this->_log ( self::TAGS_UNSUPPORTED_BY_SAVE_OF_APC_BACKEND );
		return array ();
	}
	
	/**
	 * Return an array of stored cache ids which match any given tags
	 *
	 * In case of multiple tags, a logical AND is made between tags
	 *
	 * @param array $tags array of tags
	 * @return array array of any matching cache ids (string)
	 */
	public function getIdsMatchingAnyTags($tags = array()) {
		$this->_log ( self::TAGS_UNSUPPORTED_BY_SAVE_OF_APC_BACKEND );
		return array ();
	}
	
	/**
	 * Return an array of stored cache ids
	 *
	 * @return array array of stored cache ids (string)
	 */
	public function getIds() {
		$res = array ();
		$array = apc_cache_info ( 'user', false );
		$records = $array ['cache_list'];
		foreach ( $records as $record ) {
			$res [] = $record ['info'];
		}
		return $res;
	}
	
	/**
	 * Return an array of metadatas for the given cache id
	 *
	 * The array must include these keys :
	 * - expire : the expire timestamp
	 * - tags : a string array of tags
	 * - mtime : timestamp of last modification time
	 *
	 * @param string $id cache id
	 * @return array array of metadatas (false if the cache id is not found)
	 */
	public function getMetadatas($id) {
		$tmp = apc_fetch ( $id );
		if (is_array ( $tmp )) {
			$data = $tmp [0];
			$mtime = $tmp [1];
			if (! isset ( $tmp [2] )) {
				// because this record is only with 1.7 release
				// if old cache records are still there...
				return false;
			}
			$lifetime = $tmp [2];
			return array ('expire' => $mtime + $lifetime, 'tags' => array (), 'mtime' => $mtime );
		}
		return false;
	}
	
	/**
	 * Give (if possible) an extra lifetime to the given cache id
	 *
	 * @param string $id cache id
	 * @param int $extraLifetime
	 * @return boolean true if ok
	 */
	public function touch($id, $extraLifetime) {
		$tmp = apc_fetch ( $id );
		if (is_array ( $tmp )) {
			$data = $tmp [0];
			$mtime = $tmp [1];
			if (! isset ( $tmp [2] )) {
				// because this record is only with 1.7 release
				// if old cache records are still there...
				return false;
			}
			$lifetime = $tmp [2];
			$newLifetime = $lifetime - (time () - $mtime) + $extraLifetime;
			if ($newLifetime <= 0) {
				return false;
			}
			apc_store ( $id, array ($data, time (), $newLifetime ), $newLifetime );
			return true;
		}
		return false;
	}
	
	/**
	 * Return an associative array of capabilities (booleans) of the backend
	 *
	 * The array must include these keys :
	 * - automatic_cleaning (is automating cleaning necessary)
	 * - tags (are tags supported)
	 * - expired_read (is it possible to read expired cache records
	 * (for doNotTestCacheValidity option for example))
	 * - priority does the backend deal with priority when saving
	 * - infinite_lifetime (is infinite lifetime can work with this backend)
	 * - get_list (is it possible to get the list of cache ids and the complete list of tags)
	 *
	 * @return array associative of with capabilities
	 */
	public function getCapabilities() {
		return array ('automatic_cleaning' => false, 'tags' => false, 'expired_read' => false, 'priority' => false, 'infinite_lifetime' => false, 'get_list' => true );
	}

}
